Electric circuit interrupter



p 1936- G. A. JUHLlN ET AL 2,056,009

ELECTRIC CIRCUIT INTERRUPTER Filed April 5, 1934 TO CURRENT TRANSFORMER 7 25 n i 9% \4 c con nnsssn AIR g /0 /6 g 7 g i I /5 g g I M Inventors:

Gustaf Adolf Juhlin, William A. Coates,

Their Attornqg- Patented Sept. 29, 1936 PATENT 01-1-1012 2,050,009 ELECTRIC CIRCUIT m'rnnnur'rnn Gustaf Adolf Jllhlin, 'limperley, and William AnselmOoatqBowdemEngll-Mi l msto General Electric New York Company, a corporation of Application April 5, 1984, Serial No. 719,134 In Great Britain All!!! 10. 1933 5 com. (cum-150) l'hisinventionrielateatothefluidbreakoroil immersed type of circuit interrupters. Electric circuit interrupters of this kind are known in which a moving contact moves through one or 5 more passages into and out of a casing or shrouding forming a chamber in which the fixed contact of the interrupter is located and in which a body of arc-extinguishing or insulating fluid is segregated from the remaining part of the insulat- 10 ing fluid in the oil tank. Such chambers are commonly known as explosion pots. In circuit interrupters or this kind when the connection between the fixed and moving contacts is broken anarcisformedand apressureissetup within 15 the explosion pot which as the moving contact moves out of the explosion pot causes a blast of oil and/or gas to be projected over the surface of the moving contactwhich extinguishes the are formed between the contacts, or. at least so 90 increases the resistance of the arc path; as to The blast of oil or gas may issue through the orifice by whichthe moving contact enters and 25 leaves the explosion pot and/or through one or tinction, but in all such inventions the oil is 40 introduced into the main tank or containenand passes thenceacmss the contacts towards the airspace'in thetop'ofsuchatank.

A principal object of the present invention is the provision of an improved liquid immersed cir- 4 cuit interrupter which is eifectiveefilciently to interrupt high tension power circuits throughout the operating range of current values.

According to one aspect of the present invention an oil immersed circuit interrupter comprises a tubular leading-in conductor and a confined space said conductor and in communication with the interior thereof, into which space insulating liquid under pressure may be supplied, the arrangement being such that on breaking the cirwit. a suitable valve is operated which releases the supply of said insulating 1m- 7 uid, w ich is ejected from the tubular conductor into the explosion space.

This invention will be more fullyset forth in the following description referring to the accompanying drawing, and the features of novelty which characterize this invention will be pointed out with particularity in the claims annexed to and rorming a part of this specification.

Referring more particularly to the drawing, 10

1 is an elevational view, partly in section and partly diagrammatic, illustrating an electric circuit interrupter embodying the present invention, and Fig. 2 is an elevational sectional view 01' a. modified form of the explosion chamber shown by Fig. 1.

In the drawing I is a tubular leading-in conductor surrounded by a condenser bushing 2.

Around the contact and bushing is an annular space I, enclosed by an arc shield 4 preferably of porcelain, and as shown completed by a casinglandaflansedbushingi. Theendofthe space being closed by the explosion pot I, clearly the enclosure of the space within the arc shield might be completed in other ways. The explosion pot. 1 forms an explosion or interrupting chamber I and a side chamber I which is partially separated from the explosion chamber by a partition in.

In an alternative construction as shown by Fig.2,theopenin'gat the bottom endatthetube Iistakendirectlyintotheauxiliarychamberl, which is completely separated from the main arcing chamber 1. Thus all insulating liquid under pressure in thchamber I is forced to traverse the arc path at right angles along the channels it, and no portion can escape through the central opening I.

Aseriesofplates ll formlateralpassages l2 whilst the moving contact It tunnel it through the plates H spring contacts Ii. I

Normally the chambers I, and I and passages are filled with oil and when the circuit is broken the explosion caused by the arc forces the oil-partly down the tunnel l4 and then across through the lateral passages l2, and partly around the partition is into the chamber I and thence through the lateral passages I! so as to breakthearc. Inthe explosion chamber type ofso switch the blast pressure is dependent on the arc current. Accordingly, when the arc current'is low the blast pressure may be inadequate. In applying the present invention to such a contoengage with vstruction additional oil-issupplicd \mGeriiresss passesalong a o' sure from a separate source such as through a pipe l'l to the chamber 3 whence it passes through an aperture l8 into the interior of the tubular conductor I.

In the arrangement shown by way of example,

a source of oil pressure, generally indicated at 20, is connected to the pipe II, a valve 2i controlling the application of pressure.- The source 20 may suitably comprise an oil storage tank 22 and a bottle of compressed air 23. v

The valve 2|, which is normally biased closed by a spring 24, is suitably connected to a solenoid 25 energized from the usual current transformer. When the current transformer is energized in response to excess current to trip the breaker in the usual manner (not shown), the valve 2! is also opened to connect the oil pressure sourceili with the explosion chamber. I

It will; of course, be apparent that a mechanical arrangement may be used if desired to interconnect the breaker trip mechanism and valve 2i.

when the switch is closed, the valve associated with the conventional circuit breaker mechanism closes the source of supply to II, and thus prevents emission of oil from the interior of contact I. When, however, the trip mechanism is operated in order to break the circuit, the valve also opens, permitting emission of oil from the interior of tubular conductor I into the explosion chamber, and'this will augment and assist the oil pressure caused bythe arc, in the manner explained above. It will therefore be noted that the additional oil is admitted to the explosion chamber under pressure fror'na source separate from and independent of the arc pressure generated in the explosion pot. The conductor I need only be hollow at the lower end so as to provide a passage through the hole Hi from chamber 3 to explosion pot 8 or auxiliary chamber 9. I

It should be understood that this invention'is not limited to specific details of construction and arrangement thereof herein illustrated, and that changes and modifications may occur to one skilled in the art without departing from the spirit of this invention.

, We claim:

1. A liquid immersed circuit interrupter comprisingfixed and moving contacts, an explosion pot .containing oil surrounding said contacts, means forming oil passages arranged so that oil is forced by are pressure generated in said pot along said passages laterally across the path of the moving contact. andmeans for supplying to saidexplosion not upon opening or the circuit additional oil under pressure from a separate interrupted.

source during the breaking of the circuit for augmenting said arc pressure at low current.

2. A liquid immersed circuit interrupter comprising fixed and moving contacts, a tubular leading-in conductor terminating in said fixed contact, an explosion pot having exhaust passages surrounding said contacts, the arc pressure generated in said pot upon separation of said contacts directing arc-extinguishing jets of liquid through said passages, and means for admitting upon opening of the circuit insulating liquid under pressure from a source other than the explosion chamber pressure through said tubular lead in to said explosion pot for augmenting said are pressure at low current.

3. A fluid immersed circuit interrupter comprising relatively movable contact structure, means forming an interrupting chamber within which said contact structure coacts and within which arc pressure is generated upon opening of the circuit, said arc pressure expelling fluid from said chamber through the arc path for extinguishing the arc, and means for directing across the arc path additional fluid under pressure from a source independent of said arc pressure in accordance with the circuit opening operation.

4. A fluid immersed circuit interrupter comprising relatively movable contact structure, an explosion pot containing an arc-extinguishing fluid surrounding said contact structure in the closed circuit position, said pot having an exhaust passage arranged with respect to said contact structure so that the arc pressure generated in said pot upon opening of the circuit expels fluid through said passage into the arc path, and means for admitting to said pot 'in accordance with each circuit opening operation additional arc-extinguishing fluid under pressure from a source other than said explosion pot pressure for augmenting at low current said are pressure.

5. A liquid immersed circuit interrupter comprising an explosion pot containing an'arc-extinguishing liquid, relatively movable contact structure coacting in said pot, said pot having an exhaus't passage through which the movable contact structure is actuated to open and closed circuit positions, the'arc pressure generated in said pot upon opening, of the circuit expelling liquidthrough said passage into the arc path, and means f5r admitting to said pot additional arc extinguishing liquid under pressure from a source independent of the value of current to be GUs'rAr comm.

WILLIAM ANSELM coarse. 

